[ETL]

"The geography of Indonesia is dominated by volcanoes that are formed due to subduction zones between the Eurasian plate and the Indo-Australian plate. Some of the volcanoes are notable for their eruptions, for instance, Krakatau for its global effects in 1883,[1] Lake Toba for its supervolcanic eruption estimated to have occurred 74,000 Before Present which was responsible for six years of volcanic winter,[2] and Mount Tambora for the most violent eruption in recorded history in 1815.[3]"

http://en.wikipedia.org/wiki/List_of_volcanoes_in_Indonesia

[Vaquero]

in prehistory there was Toba, now lake toba, a huge caldera which is missing on this map.

they say that the human race was brought down to 4 digits numbers due to its eruption around 73,000 BP.

[Beowulf9]

This is fabulous. Sumatra is a hotbed, I expect it would never happen, but what if say 1/4 or 1/2 of these volcanoes erupted at once?

Great place to understand the mechanisms of volcanic activity.